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العنوان
Genetic improvement and gene expression of gamma-aminobutyric acid (GABA) producing psychobiotic bacteria \
المؤلف
Fayad, Maryam Eldesoky Mohammed Eldesoky.
هيئة الاعداد
باحث / مريم الدسوقي محمد الدسوقي فياض
مشرف / سعاد أحمد عبد الله
مشرف / صفا شعبان حافظ
مشرف / شيرين عبد الحميد محمد
تاريخ النشر
2024.
عدد الصفحات
402 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
علوم النبات
تاريخ الإجازة
1/1/2024
مكان الإجازة
جامعة عين شمس - كلية البنات - النبات
الفهرس
Only 14 pages are availabe for public view

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from 402

Abstract

Psychobiotics are unique group of probiotics with potential to improve mental health via production of neuroactive compounds such as gamma-aminobutyric acid (GABA). This GABA and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. The demand for new biological sources of GABA has been rising steadily. This study aimed to evaluate the gamma-aminobutyric acid (GABA) producing lactic acid bacterial isolates from fermented food to be used as potential psychobiotic. Therefore, the current study reported the isolation of 110 presumptive lactic acid bacteria (LAB) and their screening for GABA synthesis from monosodium glutamate (MSG) using Thin-Layer chromatography (TLC). The three isolates MROMI.22, MGOLIV.25 and MGOLIV.28 were selected as a high GABA producer. The GABA content of MROMI.22, MGOLIV.25 and MGOLIV.28 cell free supernatant (CFS) was quantitatively determined by Gas chromatography-Mass Spectrometry (GC-MS) to be 8.61 mg/ml, 9.02 mg/ml and 10.16 mg/ml, respectively. The three selected isolates were identified by 16S rRNA as L. rhamnosus MROMI.22, L. casei MGOLIV.25 and L. chiayiensis MGOLIV.28 under accession No. ON796545, ON796544 and ON796543, respectively. Moreover, the three selected strains demonstrated promising probiotic potentials, γ-hemolysis and could resist low pH (2.5) and (0.3%) bile salt concentration. It also exhibited antimicrobial activity against highly pathogenic strains. In addition, the three selected strains showed antiproliferative and antioxidant properties. The glutamic acid decarboxylase (GAD) genes were detected, gadC in L. rhamnosus MROMI.22, L. casei MGOLIV.25 and L. chiayiensis MGOLIV.28 while gadB was only detected in L. rhamnosus MROMI.22 by using specific primers. The protoplast fusion between the two parental strains (L.chiayiensis MGOLIV.28 and L. rhamnosus MROMI.22) were used to develop lactic acid bacterial strains with high GABA production. Intriguingly, three fusants (12MM, 18MM and 34MM) showed an increase in GABA production, compared to its parental strains. The ultimate yield was improved to 583.70 mg/ml by 12MM fusant. The findings of this study suggest that the L. chiayiensis MGOLIV.28 strain could be used as a novel psychobiotics in the development of GABA rich healthy food products.